The Collaborative International Dictionary of English v.0.48:

Steerage \Steer"age\ (st[=e]r"[asl]j; 48), n.
   1. The act or practice of steering, or directing; as, the
      steerage of a ship.
      [1913 Webster]

            He left the city, and, in a most tempestuous season,
            forsook the helm and steerage of the commonwealth.
                                                  --Milton.
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   2. (Naut.)
      (a) The effect of the helm on a ship; the manner in which
          an individual ship is affected by the helm.
      (b) The hinder part of a vessel; the stern. [R.] --Swift.
      (c) Properly, the space in the after part of a vessel,
          under the cabin, but used generally to indicate any
          part of a vessel having the poorest accommodations and
          occupied by passengers paying the lowest rate of fare.
          [1913 Webster]

   3. Direction; regulation; management; guidance.
      [1913 Webster]

            He that hath the steerage of my course. --Shak.
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   4. That by which a course is directed. [R.]
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            Here he hung on high,
            The steerage of his wings.            --Dryden.
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   Steerage passenger, a passenger who takes passage in the
      steerage of a vessel.
      [1913 Webster]

WordNet (r) 3.0 (2006):

steerage
    n 1: the cheapest accommodations on a passenger ship
    2: the act of steering a ship [syn: steering, steerage]